Question

我正在尝试编写一个代码，通过用户获取数字并读取字符'e'或''（空格）也是数字。我的意思是数字'e'或空格'e'数字'e'或空格等等。但我得到荒谬的数字。该程序将显示添加的数字。如果输入'\ n'，则停止采取数字（scanf将停止）。（我很抱歉，因为我对标题一无所知）我哪里错了。谢谢你们所有赞赏的答案。

示例输入：

e 1 8 7 2 3 6
或
e 1 e 8 e 7 e 2 e 3 e 6

    #include <stdio.h>

    #define MAX 10

    void addq ( int *, int, int *, int * ) ;
    void test();

    int main( )
    {

        test();
        return 0;
    }


    void test(){

        int arr[MAX] ;
        int i, front, rear,num ;
        char ch;

        front = rear = -1 ;
        scanf("%c",&ch);
        /* initialise data member */
        switch(ch){

        case 'e':
        case ' ':
            for ( i = 0 ; i < MAX; i++ ){
            arr[i] = scanf("%d",&num);
            scanf("%c",&ch);
            addq ( arr, num, &front, &rear );
            }
            break;

        }

        printf ( "\nElements in the circular queue: " ) ;
        display ( arr ) ;

}
void display ( int * arr )
{
int i ;
printf ( "\n" ) ;
for ( i = 0 ; i < MAX ; i++ )
    printf ( "%d\t", arr[i] ) ;
printf ( "\n" ) ;
}
    /* adds an element to the queue */
    void addq ( int *arr, int item, int *pfront, int *prear )
    {
        if ( ( *prear == MAX - 1 && *pfront == 0 ) || (  *prear + 1 == *pfront ) )
        {
            printf ( "\nQueue is full." ) ;
            return ;
        }

        if ( *prear == MAX - 1 )
            *prear = 0 ;
        else
            ( *prear )++ ;

        arr[*prear] = item ;

        if ( *pfront == -1 )
            *pfront = 0 ;
    }

Answer 1

使用时

scanf("%c",&ch);

它会跳过空格。你应该使用

int ch; // Use type int, not char.
ch = fgetc(stdin);

Answer 2

#include <stdio.h>

#define MAX 10

typedef struct q {
    int arr[MAX];
    int front, rear;
} Q;

void init_q(Q *q);
void add_q (Q *q, int v);
void display_q(Q *q);
void test();

int main( ){
    test();
    return 0;
}

void test(){
    int num, end = 0;
    char ch;
    Q q;
    init_q(&q);

    scanf("%c", &ch);
    while(!end){
        switch(ch){
        case 'e':
        case ' ':
            if(1==scanf("%d", &num))
                add_q(&q, num);
            scanf("%c", &ch);
            break;
        case '\n':
            end = 1;
            break;
        default:
            printf("invalid input(%c)\n", ch);
            scanf("%c", &ch);
        }
    }

    printf("\nElements in the circular queue: ") ;
    display_q(&q) ;
}

void init_q(Q *q){
    q->front = q->rear = -1;
}
int empty_q(Q *q){
    return q->front == -1;
}
int full_q(Q *q){
    return (q->rear == MAX - 1 && q->front == 0) || q->rear + 1 == q->front;
}
void add_q (Q *q, int item){
    if(full_q(q)){
        printf( "\nQueue is full.\n");
        return ;
    }

    if( q->rear == MAX - 1 )
        q->rear = 0;
    else
        q->rear++;

    q->arr[q->rear] = item;

    if(q->front == -1 )
        q->front = 0;
}
void display_q(Q *q){
    if(!empty_q(q)){
        int i = q->front;
        printf("\n");
        for(;;){
            printf("%d\t", q->arr[i]);
            if(i++ == q->rear)
                break;
            if(i == MAX)
                i = 0;
        }
        printf("\n");
    }
}

通过用户开关盒进行字符扫描

2 个答案: